[Tutor] Connecting Py 2.7 with visa

[Wilson, Pete]

Pip-for-windows worked great! Bob's your uncle! Case closed.

Pete

> -----Original Message-----
> From: Tutor [mailto:tutor-bounces+pete.wilson=atmel.com at python.org] On
> Behalf Of Mark Lawrence
> Sent: Friday, May 15, 2015 7:15 PM
> To: tutor at python.org
> Subject: Re: [Tutor] Connecting Py 2.7 with visa
> 
> On 15/05/2015 23:12, Wilson, Pete wrote:
> > Greetings I am trying to write a test executive program using python
> 2.7 on a windows 7 computer. I want to connect to  a Keithley 2100
> voltmeter using National Instruments VISA. I am having trouble
> installing pyvisa. All the documentation refers to using 'pip' and a
> command line "$ pip install pyvisa" . What interface or console is
> this? "$" prompt looks like a Linux command line. How do we do this
> with windows?
> >
> 
> It's a Windows command line prompt.  You can get this by hitting the
> Windows logo key with 'R' and then entering cmd<return>.  However the
> simplest way for you I think is to download this
> https://sites.google.com/site/pydatalog/python/pip-for-windows
> 
> > Do I have to do this? Or can I use the native visa module in Python
> 2.7? Using the help() and dir() features I can get some basic
> information about visa, but the functions have changed, like
> visa.ResourceManager.open_resource is not working. I really liked this
> function... Are there any examples of how to use this new visa? I have
> some working code below that uses pyvisa, can it be converted?
> >
> 
> Please help us to help you.  Stating "is not working" is less than
> useless, please show us exactly what happens.  Cut and paste any
> output, don't rely on typing it as this often results in further errors
> that just confuse the issue.
> 
> > def update_current():
> >      import visa
> >
> >      rm = visa.ResourceManager()
> >      rm.list_resources()
> >
> >      current_1_ma = ""
> >      exe_check = "PASS"
> >
> >      try:
> >          dut_data = open("dut_data.txt", "w")
> >      except:
> >          exe_check = "FAIL"
> 
> Don't use bare excepts as it's asking for trouble.  Much better to
> leave out the error handling to start with and just let your
> programming errors bubble up as stack traces.  Then add in appropriate
> things to catch.  In the above FileNotFoundError amongst others seems
> suitable.
> 
> --
> My fellow Pythonistas, ask not what our language can do for you, ask
> what you can do for our language.
> 
> Mark Lawrence
> 
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